PROPAGATING HOUSE. 43 



zier's points, but put no putty on the outside use noth- 

 ing but thick, pure white lead paint. The size of glass 

 is immaterial, but if the best and heaviest is used, then 

 the panes may be of any size, from 8x10 up to 10x16. 

 The engraving shows the interior arrangement very 

 minutely, except the posts which will be necessary for 

 supporting the roof. The house stands its longest way 

 north and south ; the southern end is of glass, which 

 may reach to the ground, or stop at the height of the 

 frames. At the north end is the furnace room, where 

 also the potting bench, pots, etc., may be kept. The 

 best and most economical mode of heating a large house 

 is by means of steam or hot water. For this purpose 

 there are several kinds of boilers in market, many of 

 which are very good. 



The hot-water pipes should lie side by side, instead 

 of one over the other as they are usually placed in ordi- 

 nary greenhouses. The flow-pipe passes under one of 

 the side frames, thence through and back under the 

 middle one, and then under the frame on the opposite 

 side. The return pipe passes back along by its side, 

 both lying on iron rests made for the purpose. This 

 arrangement gives eight pipes the whole length of the 

 house, besides the elbows and the few feet that it takes 

 to cross the end. The center frame has four pipes under 

 it, while the side frames have but two. 



The center frame may be used for starting those 

 varieties that are the most difficult to strike, or the pipes 

 may only pass under the two outside frames, and the 

 center one be used for the plants when they are first 

 placed in the small pots or the pipes may, pass under 

 the center frame and return under the outside ones, 

 without returning, as shown. 



If the house is twenty or more feet in width, then 

 for convenience the center frame should be double the 

 width of the outside ones, and in that case the four pipes 



